If you want to use certain parts of the Commerce Manager (e.g. Marketing -> Promotion -> “Order: Buy X, get N quantity of Y at a discount”. -> Catalog entries picker, the Commerce default Lucene search indexer must be active.
Else you get this error inside the picker window:
System.IO.FileNotFoundException: no segments* file found in Lucene.Net.Store.FSDirectory
The searchindex creation can be triggered manually through Manager -> Administration -> System settings -> Search Index.
Scheduled jobs should be available in CMS but here is how to trigger the indexing through code:
via Searching and Indexing.
Build index command
SearchManager searchManager = new SearchManager(applicationName);
searchManager.BuildIndex(false);